Nonvolatile electrical control of stacking dependence in FePS3/Sc2CO2 van der Waals heterostructure

The stacking orders that have critical impacts on nonvolatile electrical control have not been well explored in two-dimensional antiferromagnetic/ferroelectric heterostructures. We constructed all six types of stacking orders (each with two polarization directions: upward and downward) in the FePS3/Sc2CO2 heterostructure with atom-to-atom interlayer alignment and systematically investigated their electronic structures and magnetism through first-principles calculations. We found that the heterostructure maintains the semiconductor and zigzag antiferromagnetic (zAFM) ground state identical to FePS3 monolayer when polarization is downward, while it becomes metal when polarization is upward, and its magnetic ground state transitions to ferromagnetic (FM) in AB and ABR stacking orders, while maintaining the zAFM ground state in other stacking orders. Moreover, AB stacking order is the most energetically favorable for both polarization upward and downward, indicating that polarization reversal tends not to alter AB stacking order, which helps reduce energy consumption during switching between zAFM semiconductor and FM metal, and this property can be easily generalized in other (anti)ferromagnetic/ferroelectric heterostructures. The physical mechanisms of nonvolatile electrical control and stacking dependence for electronic structure and magnetism are explained in detail through the band alignment, charge transfer, and atomic structural deformation caused by interlayer magnetoelectric coupling. In addition, the different strain response properties of electronic structure and magnetism in different stacking orders further enhance the tunability of the heterostructure. Our work achieved high tunability of the antiferromagnetic/ferroelectric heterostructure through nonvolatile electrical control of stacking dependence and proposed a simple material design strategy for optimizing stacking order control to improve the energy efficiency ratio of nonvolatile electrical control.